A plunger is a common evice used to release stoppages in plumbing. The tool consists of a rubber cup with an attached stick "shaft", usually made of wood or bronze. The cup is pushed down against the drain, and either pressed hard into the drain to force air in, or is pushed down until the rubber cup is flattened, then pulled out, causing a vacuum. The intent is to loosen or break up a clog, excessive material, or other blockage in a sink, toilet, bathtub, shower, etc.